NEW YORK (Reuters Health) - Regular aerobic exercise reduces fatty liver in obese individuals, even without changes in body weight or abdominal fat, Australian researchers report.

"Weight loss is often the primary intent for prescribing lifestyle therapy in the management of obesity-related fatty liver disease," lead researcher Dr. Nathan A. Johnson of the University of Sydney noted in an email to Reuters Health. "Yet, it is now recognized that being physically fit can protect against cardio-metabolic risk, independent of adiposity," he added.

As reported in the October issue of Hepatology, Dr. Johnson and colleagues used magnetic resonance imaging and proton magnetic resonance spectroscopy to assess the effect of aerobic training on hepatic, blood, abdominal and muscle lipids in 19 obese sedentary adults.

Twelve participants were assigned to a 4-week aerobic cycling program and 7 followed a home stretching routine (the control group).

After 4 weeks, body weight and body mass index remained unchanged, but cardiorespiratory fitness improved significantly in the exercise group versus the control group, the team reports.

Moreover, compared to baseline, the researchers noted a 21% reduction in hepatic triglycerides, a 12% decline in visceral adipose tissue and a 14% reduction in plasma free fatty acids in the aerobic exercise group.

"The benefit was achieved using an exercise dose on the lower end of the range currently recommended for health promotion, and significantly lower than that advocated for the management of overweight and obesity," he added.

This finding, Dr. Johnson concluded, "is important not just for reducing the burden of liver-related morbidity and mortality, but also for the broader obesity, cardiovascular disease and insulin resistance epidemics, in which hepatic steatosis plays a central role."